A Fourier analysis method is used to accurately determine not only the absolute phase but also the tempuralpulse phase of an isolated few-cycle （chirped） laser pulse. This method is independent of the pulse shape an...A Fourier analysis method is used to accurately determine not only the absolute phase but also the tempuralpulse phase of an isolated few-cycle （chirped） laser pulse. This method is independent of the pulse shape and can fully characterize the light wave even though only a few samples per optical cycle are available. It pavas the way for investigating the absolute phase-dependent extreme nonlinear optics, and the evolutions of the absolute phase and the temporal-pulse phase of few-cycle laser pulses.展开更多
We theoretically investigate the characteristics of terahertz(THz) radiation from monolayer graphene exposed to normal incident few-cycle laser pulses, by numerically solving the extended semiconductor Bloch equations...We theoretically investigate the characteristics of terahertz(THz) radiation from monolayer graphene exposed to normal incident few-cycle laser pulses, by numerically solving the extended semiconductor Bloch equations. Our simulations show that the THz spectra in low frequency regions are highly dependent on the carrier envelope phase(CEP) of driving laser pulses. Using an optimal CEP of few-cycle laser pulses, we can obtain broadband strong THz waves, due to the symmetry breaking of the laser-graphene system. Our results also show that the strength of the THz spectra depend on both the intensity and central wavelength of the laser pulses. The intensity dependence of the THz wave can be described by the excitation rate of graphene, while wavelength dependence can be traced back to the band velocity and the population of graphene. We find that a near single-cycle THz pulse can be obtained from graphene driven by a mid-infrared laser pulse.展开更多
With the classical ensemble model, we investigate nonsequential double ionization （NSDI） of xenon atoms using 780 nm, 0.25 PW/cm2 elliptically polarized few-cycle laser pulses. The momentum distribution of correlate...With the classical ensemble model, we investigate nonsequential double ionization （NSDI） of xenon atoms using 780 nm, 0.25 PW/cm2 elliptically polarized few-cycle laser pulses. The momentum distribution of correlated electron along the long axis o~ the laser polarization plane shows an obvious V-like structure locating at the third quadrant, and the momentum along the short axis of the laser polarization plane are mainly distributed in the second and fourth quadrants. Moreover, we demonstrate that the Coulomb repulsion interaction plays a decisive role to the above results. By back analyzing the class/ca/ trajectories of NSDI, we find that there are two kinds of recollision trajectories mainly contribute to NSDI, and the different microscopic dynamics for the two kinds of trajectories are clearly explored.展开更多
We demonstrate a compact Ti:sapphire oscillator with ring cavity configuration.By optimizing the intra-cavity dispersion with chirped mirrors,pulses with repetition rate of 1.1 GHz are coupled out by the uncoated wedg...We demonstrate a compact Ti:sapphire oscillator with ring cavity configuration.By optimizing the intra-cavity dispersion with chirped mirrors,pulses with repetition rate of 1.1 GHz are coupled out by the uncoated wedges in the cavity.Under 7W CW pump laser centered at 532 nm,the average power of the output pulses is about 30 mW,the duration is less than 10fs and the spectrum spans from 670 nm to 920 nm.展开更多
基金Project supported by the National Natural Science Foundation of China （Grant No 60478002）, and the Basic Research Key Foundation of Shanghai （Grant Nos 04JC14036 and 05DJ14003）.
文摘A Fourier analysis method is used to accurately determine not only the absolute phase but also the tempuralpulse phase of an isolated few-cycle （chirped） laser pulse. This method is independent of the pulse shape and can fully characterize the light wave even though only a few samples per optical cycle are available. It pavas the way for investigating the absolute phase-dependent extreme nonlinear optics, and the evolutions of the absolute phase and the temporal-pulse phase of few-cycle laser pulses.
基金Supported by the National Natural Science Foundation of China (Grant Nos.11764038,11864037,11765018,and 91850209)。
文摘We theoretically investigate the characteristics of terahertz(THz) radiation from monolayer graphene exposed to normal incident few-cycle laser pulses, by numerically solving the extended semiconductor Bloch equations. Our simulations show that the THz spectra in low frequency regions are highly dependent on the carrier envelope phase(CEP) of driving laser pulses. Using an optimal CEP of few-cycle laser pulses, we can obtain broadband strong THz waves, due to the symmetry breaking of the laser-graphene system. Our results also show that the strength of the THz spectra depend on both the intensity and central wavelength of the laser pulses. The intensity dependence of the THz wave can be described by the excitation rate of graphene, while wavelength dependence can be traced back to the band velocity and the population of graphene. We find that a near single-cycle THz pulse can be obtained from graphene driven by a mid-infrared laser pulse.
基金Supported by the National Natural Science Foundation of China under Grant Nos.11005088and11047145the Basic and Advanced Technology of Henan Province of China under Grant Nos.102300410241and112300410021the Scientific Research Foundation of Education Department of Henan Province of China under Grant Nos.2011B140018and13A140774
文摘With the classical ensemble model, we investigate nonsequential double ionization （NSDI） of xenon atoms using 780 nm, 0.25 PW/cm2 elliptically polarized few-cycle laser pulses. The momentum distribution of correlated electron along the long axis o~ the laser polarization plane shows an obvious V-like structure locating at the third quadrant, and the momentum along the short axis of the laser polarization plane are mainly distributed in the second and fourth quadrants. Moreover, we demonstrate that the Coulomb repulsion interaction plays a decisive role to the above results. By back analyzing the class/ca/ trajectories of NSDI, we find that there are two kinds of recollision trajectories mainly contribute to NSDI, and the different microscopic dynamics for the two kinds of trajectories are clearly explored.
基金Supported by the National Basic Research Program of China (2006CB806000)the Natural Science Foundation of China (10875072)the Open fund of the State Key Laboratory of High Field Laser Physics , Shanghai Institute of Optics and Fine Mechanics
基金Supported by the National Natural Science Foundation of China(12064028)Jiangxi Provincial Natural Science Foundation(20232BAB201045)Open Foundation of Key Laboratory of Nondestructive Testing Technology(Ministry of Education)(EW202108218)。
基金Supported by the National Natural Science Foundation of China (Grant Nos.60490281 and 60321003)National Basic Research Program of China (Grant No.2007CB815104)
文摘We demonstrate a compact Ti:sapphire oscillator with ring cavity configuration.By optimizing the intra-cavity dispersion with chirped mirrors,pulses with repetition rate of 1.1 GHz are coupled out by the uncoated wedges in the cavity.Under 7W CW pump laser centered at 532 nm,the average power of the output pulses is about 30 mW,the duration is less than 10fs and the spectrum spans from 670 nm to 920 nm.
